1. Field of the Invention
The present invention relates to an integrated circuit semiconductor device mounting apparatus and method for the mounting of a semiconductor device to a substrate. More specifically, the present invention relates to an apparatus and method for the mounting of a substrate to any semiconductor device or a flip-chip type semiconductor device.
2. State of the Art
A conventional method for the mounting of a semiconductor device to a substrate comprises the steps of supplying a packaged semiconductor device having a lead projecting from a side face thereof to a supply position, vacuuming the packaged semiconductor device at the supply position by a vacuum mounting head, recognizing the image and the position of the packaged semiconductor device by a component recognizing device, mounting the packaged semiconductor device on a mounting position of a circuit board by changing or correcting the, position of the packaged semiconductor device head by the vacuum mounting head, and soldering the lead of the packaged semiconductor device to a circuit of the circuit board.
Flip-chip bonding is a well known alternative for attaching a semiconductor device to a substrate and electrically connecting the semiconductor device to the circuits of a substrate, rather than the use of a lead frame to connect a semiconductor device to the circuits of a substrate where the lead frame mechanically holds the semiconductor device and is electrically connected thereto by bond wires with the combination of the lead frame and semiconductor device being encapsulated. In flip-chip bonding, a bond pad of the semiconductor device is bonded using reflowed solder to the desired circuit of a substrate by having the solder bumped pads on the active surface or face of a semiconductor device contacting the circuits of a substrate.
In order to increase the response of semiconductor devices and increase the density of semiconductor devices on substrates it is desirable to use flip-chip bonding for semiconductor devices mounted on substrates.
Since it is necessary to provide the semiconductor device to a supply station to be flip-chip bonded to the substrate, unless care is taken in the transport and handling of the semiconductor devices, damage to the solder-bumped bond pads of the semiconductor device can occur. If the semiconductor devices are transported and handled in the active surface or face up position, damage to the circuitry of the semiconductor device from the vacuum handling device may occur. Therefore, it is desirable to transport and handle the semiconductor devices in an active surface or face down orientation.
Since the mounting surface of substrates is not planar, problems arrive in aligning the semiconductor device to the substrate and in providing sufficient force for the flip-chip mounting of the semiconductor device thereto.
The present invention comprises an apparatus and method for attaching a semiconductor device to a substrate wherein the semiconductor device is positioned with the substrate being subsequently attached thereto being located thereabove.
In one embodiment, the apparatus and method comprises an apparatus for attaching a substrate above a semiconductor device located therebelow using an adhesive and solder paste.
In another embodiment, the apparatus and method comprises a system for attaching a semiconductor device or die to each substrate of a plurality of substrates and includes indexing apparatus for supplying and advancing the plurality of substrates for semiconductor devices in a lead substrate-by-substrate sequence. Each substrate of the plurality of substrates has an attaching surface to which a semiconductor device or die is to be attached. The system also includes a source of curable adhesive. Application apparatus are configured for receiving the plurality of substrates for semiconductor devices in the substrate-by-substrate sequence. The application apparatus is connected to the source of curable adhesive for receiving curable adhesive therefrom. The application apparatus is also configured for applying a metered amount of the curable adhesive in a preselected pattern to the application surface of each substrate of the plurality of substrates. The application apparatus then supplies the substrates with the curable adhesive applied thereto.
The system also includes a source of semiconductor devices to supply semiconductor devices in; a semiconductor device-by-semiconductor device sequence. Attaching apparatus is positioned relative to the source of semiconductor devices to obtain each semiconductor device of the plurality of semiconductor devices in the semiconductor device-by-semiconductor device sequence. The attaching apparatus is also positioned to receive the substrates with the curable adhesive applied thereto in substrate by substrate sequence from the application apparatus. The attaching apparatus is also configured to attach one of the said devices to a corresponding substrate in a substrate-by-substrate sequence by urging the die into contact with the curable adhesive of each substrate and holding each of the semiconductor devices in contact with the curable adhesive for a preselected period. That is, at least one semiconductor device is attached to each substrate. Control apparatus is provided in the system to supply operation signals to operate the various components thereof.
Alternately, the application apparatus supplies and applies segments of adhesively coated tape to the substrates, rather than a liquid or paste adhesive.
A method for applying curable adhesive to each lead frame of a plurality of substrates and a semiconductor device to each such substrate includes providing a system and operating the system to supply semiconductor devices and substrates relative to application apparatus and attaching apparatus. The system is also operated to apply adhesive to a semiconductor device site of each substrate and to then attach a semiconductor device to the adhesive at the semiconductor device site. Preferably, the adhesive is a snap curable epoxy with a cure time of about 1 second. Even more preferably, the application apparatus includes a pressing structure which includes a block that heats the semiconductor devices to a temperature from about 200 degrees centigrade to about 225 degrees centigrade.
Alternately, segments of adhesively coated tape are supplied and applied to each substrate, rather than an adhesive.